Add ls in tox commands

tox.ini

 [tox]
 envlist = py38, py39, flake8
 
-;[travis]
-;python =
-;    3.9: py39
-;    3.8: py38
-
 [testenv:flake8]
 basepython = python
 deps = flake8
@@ -20,6 +15,7 @@ deps =
 ; requirements.txt with the pinned versions and uncomment the following line:
 ;     -r{toxinidir}/requirements.txt
 commands =
+    ls -la
     pip install -U pip
     pytest --basetemp={envtmpdir}